I would recommend use CODESYS V3 - Control Win plc.
This is the softplc without realtime capabilities and an built in OPCUA Server is included.
No externel OPC Server is needed.
Optional you could add IO's by an Ethernet based fieldbus (Ethercat/Profinet/EthernetIP.....etc)
How to start?
Download CODESYS V3http://store.codesys.com/engineering/codesys.html
-After installing and executing the CODESYS developmentsystem to our pc you need to start the plc
-use attached example project, start the plc, scan it by CODESYS and download the project and start it
- connect you OPCUA Client to the plc and browse the symbols
This is a lot easier than using an external OPC Server which offten is hard to configure.